Seal assembly for a cannula

ABSTRACT

The present disclosure relates to a seal assembly for a cannula. The cannula includes a housing having a proximal portion and a distal portion. The seal assembly is located in the proximal portion of the housing and includes a first seal including a first tri-slit, a second seal disposed co-axially and proximal to the first seal and including a second tri-slit, and a third seal disposed co-axially to the first seal and the second seal and including a central opening. A cap is coupled to the proximal portion of the housing and adjacent the third seal and includes a plurality of suture retaining features, such as tabs, for management of sutures during surgery. Fluid leakage out of the cannula, during surgery, is substantially reduced due to the leakage being limited to a channel defined by the first tri-slit, the second tri-slit, and the central opening.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to medical and surgicaldevices, and more specifically to seal assemblies for cannulas.

2. Related Art

Arthroscopic or, more generally, endoscopic surgical procedures enableclosed surgery to be performed via portals through which a variety ofelongated instruments may be passed to gain access to an internalsurgical work site. Very often a disposable cannula is inserted into theportal in order to provide a convenient passageway through which variousinstruments may be passed. Because many arthroscopic procedures requirethe use of pressurized fluid to distend and irrigate the joint beingoperated upon, the cannula must provide a sealed passageway in order toenable instruments to be passed into and out of the cannula whilemaintaining a fluid seal whether or not an instrument is in the cannulapassageway. The scaling of such cannula passageways is usuallyaccomplished by one or more elastomeric membranes attached to theproximal end of the elongated cannula.

Since the fluid at the work site is pressurized, care must be taken toavoid leakage during the time the instrument is being inserted. Currentseal assemblies for use in cannulas leak excessively and improvement onthe amount of leakage out of the cannula is desired. In addition, uponinsertion of an instrument into an opening on the seals of currentmodels, fluid sprays out of the opening. In order to prevent this fromoccurring, the seal is covered by placing a spray shield on the proximalend of the cannula. FIG. 1 shows a current cannula model 10 that has aspray shield 11 covering the seal assembly 12 at the proximal end 13 ofthe cannula 10. However, the size of the spray shield 11 makes itdifficult for the surgeon to work in tight operative spaces. Therefore,a sealing assembly that minimizes this problem is also needed.

Furthermore, the variety of instruments which must be inserted throughthe cannula seal includes instruments of varying sizes andconfigurations. While the instrument shafts are usually cylindrical,some instruments may have unusually large or sharp distal tips which maycut a seal element upon the insertion or extraction of the instrumentthus making it less suitable for subsequent instruments which must beinserted during the same surgical procedure. It is desirable, therefore,to devise a sealing cannula which minimizes this problem.

Finally, in addition to instruments, sutures may also be passed throughthe seal assembly. In fact, the management of these sutures has becomecritical to the technical success of the surgery. Indeed, tangledsutures can terminate an arthroscopic procedure. Therefore, an approachto suture management is also needed.

SUMMARY OF THE INVENTION

The present disclosure relates to a seal assembly for a cannula. Thecannula includes a housing having a proximal portion and a distalportion. The seal assembly is located in the proximal portion of thehousing and includes a first seal including a first tri-slit, a secondseal disposed co-axially and proximal to the first seal and including asecond tri-slit, and a third seal disposed co-axially to the first sealand the second seal and including a central opening having a diameter ofbetween about 0.060 inches to about 0.120 inches. In an embodiment, acap is coupled to the proximal portion of the housing and adjacent thethird seal and includes a plurality of suture retaining features, suchas tabs, for management of sutures during surgery. In anotherembodiment, the seal assembly further includes a space located betweenthe second seal and the third seal. In yet another embodiment, the firsttri-slit and the second tri-slit are offset by an angle α, which isabout 180°. In a further embodiment, the first tri-slit, the secondtri-slit and the central opening define a channel passing through theseal assembly. Fluid leakage during surgery is limited to the channel.In yet a further embodiment, the first seal and the second seal areconfigured to form a seal against sutures and the third seal isconfigured to form a seal against shafted instruments. In an embodiment,the third seal comprises a synthetic material. In another embodiment,the third seal comprises a polymer, such as polyisoprene.

The present disclosure also relates to a seal assembly having a firstseal including a first tri-slit and at least one interlocking member, asecond seal disposed co-axially and proximal to the first seal, thesecond seal including a second tri-slit and at least one interlockingmember, and a third seal disposed co-axially and proximal to the firstseal and the second seal, the third seal including a central opening.The interlocking member of the first seal and the interlocking member ofthe second seal interlock with each other. In an embodiment, the firstseal and the second seal both include multiple interlocking members,wherein the interlocking members of the first seal and the interlockingmembers of the second seal interlock with each other. The interlockingbetween the interlocking member of the first seal and the interlockingmember of the second seal facilitates positioning of the first tri-slitand the second tri-slit at an angle α, which is about 180°, relative toeach other.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate the embodiments of the present inventionand together with the written description serve to explain theprinciples, characteristics, and features of the invention. In thedrawings:

FIG. 1 shows a perspective view of a prior art cannula having a sprayshield coupled to the proximal end of the cannula.

FIG. 2 shows an exploded perspective view of the cannula of the presentdisclosure.

FIG. 3A shows a top view of the first and second seals of the sealassembly of the present disclosure.

FIG. 3B shows a top view of the first and second seals of the presentdisclosure showing suture coming out of the tri-slits.

FIG. 4 shows a cross-sectional perspective view of the proximal portionof the cannula of the present disclosure.

FIG. 5 shows a perspective view of the cap of the present disclosure aslocated on the proximal portion of the cannula.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

An embodiment of a cannula of the present disclosure is illustrated inFIG. 2 and designated generally by reference number 100. The cannulaincludes a seal assembly for substantially reducing the amount of fluidleakage from the cannula and specifically for forming a seal againstsutures and shafted instruments.

The cannula 100, which is plastic, but could be made from other materialknown to one of ordinary skill in the art, includes a housing 101 havinga proximal portion 102 and a distal portion 103. Near the proximalportion 102, an outflow tube 112 provides a means for removing fluidfrom the inner lumen of the distal portion 103 during surgery. Although,it is also within the scope of this disclosure that the tube 112 may beused as an inflow tube for supplying fluid to the inner lumen of thedistal portion 103 during surgery. A cover 121 is detachably coupled tothe inflow tube 112 for closing off the inflow tube while the cannula100 is not in use. Located in the proximal portion 102 is a sealassembly 130. The seal assembly 130 includes a first seal 104 having afirst tri-slit 105, a second seal 106 that is disposed co-axially andproximal to the first seal 104 and includes a second tri-slit 107, and athird seal 108 that is disposed coaxially and proximal to the first seal104 and the second seal 106 and includes a central opening 109. Thefirst seal 104 and the second seal 106 both have four sides (104 a-d,106 a-d). The seals 104,106 also have openings 110,111 that extendthrough the seals 104,106. The second seal 106 sits proximal to thefirst seal 104 such that no space exists between the seals 104,106, theopenings 110,111 of both seals 104,106 are aligned, and the tri-slits105,107 are offset by an angle α, as is further shown in FIG. 3A. Forthe purposes of this disclosure, the angle α is between approximately150° and approximately 210°, but preferably is 180°. Sides (104 a-b, 106a-b) and sides (104 c-d, 106 c-d) of the seals 104,106 are made tointerlock with each other. For example, as shown in FIG. 3A, the seals104,106 include interlocking members, such as tabs 122 and detents 123,which interlock with one another. The tabs 122 and detents 123 alternatewith regards to the seals 104,106 that they are located on. Thisinterlocking feature facilitates positioning of the tri-slits 105,107 atan angle, approximately 180°, relative to each other each time the seals104,106 are assembled together. Other interlocking features, known toone of ordinary skill in the art, may be used.

Also shown in FIG. 3A, the tri-slits 105,107 are of a Y-shapedconfiguration with each slit 105,107 defining a pair of slit arms (105a-b, 107 a-b) joined together at one end 105 c,107 c and forming anobtuse angle as shown. Thus, they each define an arrow pointing in anopposed direction to each other and also define a pair of intersectionpoints 113, forming a channel, as further discussed below, that thatextends completely through both seals 104,106. Added to each pair ofarms (105 a-b, 107 a-b) are slit legs 105 d, 107 d, which are located atan angle α, or about 180°, from each other. As is shown in FIG. 3B, thetri-slits 105,107 provide a seal against the sutures 200 by having achannel, as further discussed below, that has the smallest possibleopening to the sutures 200 and substantially reduces the amount of fluidleaving the cannula. For the purposes of this disclosure, both the first104 and the second 106 seals are made from silicon. However, othermaterial known to one of ordinary skill in the art could be used,including, but not limited to, rubber, vinyl, polyurethane elastomers,or a combination of components, includingstyrene-ethylene-butylene-styrene (SEBS) block co-polymers, polyolefins,mineral oils, and silicone oils.

The third seal 108 is located proximal to the first 104 and second 106seals and includes a central opening 109, along with four other openings114 that are located around the outer diameter of the seal 108. The seal108 is in a co-axial relationship with the first 104 and second 106 sealsuch that the central opening 109 is aligned with the center 113 of thetri-slits 105,107 and the openings 114 on the outer diameter are alignedwith the openings 110,111 on the first and second seals 104,106. Asshown in FIG. 4, the central opening 109, which is between about 0.060inches to about 0.120 inches in diameter, is configured to form a sealagainst shafted instruments 140 that have a diameter that is larger thanthe opening 109. The instrument 140 is first inserted into the centralopening 109, and then through the Y-slit channel of the second seal 106.Once the instrument is inserted into the opening 109, the walls 150 ofthe opening 109 push outward toward the second seal 106, yet remainagainst the shaft of the instrument 140 to create a seal against anyfluid that may flow through the tri-slits 105,107 and towards the thirdseal 108. For the purposes of this disclosure, the central opening 109is round, but it could be of another shape. The third seal 108 ismanufactured from a polymer material, specifically polyisoprene, tosubstantially reduce the amount of tearing or wear as a result ofinsertion and/or withdrawal of sharp instruments. Other natural orsynthetic materials known to one of ordinary skill in the art, and thatwould substantially reduce the amount of tear or wear, could also beused. These materials include, but are not limited to, silicone, rubber,vinyl, polyurethane elastomers, or a combination of components,including styrene-ethylene-butylene-styrene (SEBS) block co-polymers,polyolefins, mineral oils, and silicone oils.

As mentioned above in FIG. 1, upon insertion of an instrument into anopening on the seals of current cannulas, fluid sprays out of theopening. In order to prevent this from occurring, the seal is covered byplacing a spray shield on the proximal end of the cannula. Thisadditional step is eliminated in the present disclosure by integratingthe spray shield, which in this disclosure is the third seal 108, intothe cannula. Without the spray shield covering the proximal portion ofthe cannula, the overall size of the cannula 100 is smaller, therebymaking it easier for the surgeon to work in tight operative spaces.

In addition to eliminating the step of adding a spray shield onto theproximal portion, the cannula 100 of the present disclosure alsosubstantially reduces the amount of fluid spray that occurs outside ofthe cannula 100. FIG. 4 shows a space 160 that is located between thesecond seal 106 and the third seal 108. This space 160 allows for asubstantial reduction in the amount of fluid spray that occurs outsideof the cannula 100 by causing some of the fluid that would otherwise besprayed outside of the cannula 100 to be reflected back toward thesecond seal 106. In addition to causing a reflection of the fluid, thespace 160 also substantially reduces the force required to insertsurgical instruments 140 by allowing the walls 150 of the opening tohave the space needed to push outward toward the second seal 106. Ifthis space wasn't present and the third seal 108 was against the secondseal 106, there would be no space to allow the walls 150 to push outwardand a greater amount of force would therefore be required to insert theinstrument 140.

The seal assembly 130 is placed in the proximal portion 102 of thehousing 101 such that the openings (110,111,114) of the seals(104,106,108) are placed over columns 115 that are located along theinside perimeter 116 of the proximal portion 102. These columns 115provide support for the seals (104,106,108).

A plastic cap 118 is coupled to the proximal portion 102 of the housing101 and is adjacent to the third seal 108. The cap 118 may be made fromanother material known to one of ordinary skill in the art. Having thecap 118 on the proximal portion 102 of the housing 101 compresses theseal assembly 130 and limits fluid leakage during surgery to a channel117 defined by the first tri-slit 105, second tri-slit 107, and centralopening 109, thereby substantially reducing the amount of fluid leakageout of the cannula 100. The cap 118 includes a central opening 119 and aplurality of suture retaining features 120, or tabs, for the managementof multiple strands of sutures during surgery.

There are several advantages for having the tabs 120 on the cap 118. Asshown in FIG. 5, having multiple tabs 120 on the cap 118 allows fordifferent strands of suture 201, 202 to be simultaneously arranged inseparate positions. In addition, the tabs 120 are molded into the cap118, which avoids the need for an accessory device and/or a modificationto the housing 101 by the surgeon to manage the sutures 201,202.Furthermore, the tab length extends past the proximal portion 102 of thehousing 101 to allow the capture of a suture 201,202 that is placedbehind the tab 120 and drawn upwards. Additionally, the tabs 120 aretapered to maintain secure contact with suture strands of various sizes,such as strands 201 and 202. Finally, a suture 201,202 is easily removedonce it is secured to the tab 120 without damage to the suture 201,202or housing 101. It is within the scope of this disclosure that thenumber, size, shape, length, orientation, and thickness of the tabs 120could be adjusted to make for alternative embodiments.

As various modifications could be made to the exemplary embodiments, asdescribed above with reference to the corresponding illustrations,without departing from the scope of the present disclosure, it isintended that all matter contained in the foregoing description andshown in the accompanying drawings shall be interpreted as illustrativerather than limiting. Thus, the breadth and scope of the presentdisclosure should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims appended hereto and their equivalents.

1. A seal assembly for a cannula, the cannula comprising a singlecomponent housing having a proximal portion and a distal portion, theseal assembly comprising: a first seal including a first tri-slit, thefirst seal including rounded and flat sides located around a perimeterof the first seal, each side including at least one interlocking memberdirectly attached to the first seal; a second seal disposed co-axiallyand proximal to the first seal, the second seal consisting of a secondtri-slit, the second seal including rounded and flat sides locatedaround a perimeter of the second seal, each side including at least oneinterlocking member directly attached to the second seal; and a thirdseal disposed co-axially and proximal to the first seal and the secondseal, the third seal including a central opening, wherein the sealassembly is located in the proximal portion of the housing, wherein aspace is located between the second and third seal, the space created bythe second and third seal, wherein the interlocking members of the firstseal and the interlocking members of the second seal interlock with eachother such that the rounded sides of the first seal are located adjacentto the flat sides of the second seal.
 2. The seal assembly of claim 1further comprising a cap coupled to the proximal portion of the housingand adjacent to the third seal.
 3. The seal assembly of claim 2 whereinthe cap comprises a plurality of suture retaining features formanagement of sutures during a surgery.
 4. The seal assembly of claim 3wherein the suture retaining features comprise tabs.
 5. The sealassembly of claim 1 wherein the first tri-slit and the second tri-slitare offset by an angle α.
 6. The seal assembly of claim 5 wherein theangle α is about 180°.
 7. The seal assembly of claim 1 wherein the firsttri-slit, the second tri-slit, and the central opening define a channelpassing through the seal assembly.
 8. The seal assembly of claim 1wherein the first seal and the second seal are configured to form a sealagainst sutures.
 9. The seal assembly of claim 1 wherein the third sealis configured to form a seal against shafted instruments.
 10. The sealassembly of claim 1 wherein the central opening comprises a diameter ofbetween 0.060 inches to 0.120 inches.
 11. The seal assembly of claim 1wherein the third seal comprises a synthetic material.
 12. The sealassembly of claim 1 wherein the third seal comprises a polymer material.13. The seal assembly of claim 12 wherein the polymer material comprisespolyisoprene.
 14. A cannula comprising: a single component housinghaving a proximal portion and a distal portion; a cap coupled to theproximal portion of the housing; and a seal assembly located in theproximal portion of the housing and adjacent the cap, the seal assemblycomprising: a first seal including a first tri-slit, the first sealincluding rounded and flat sides located around a perimeter of the firstseal, each side including at least one interlocking member directlyattached to the first seal; a second seal disposed co-axially andproximal to the first seal, the second seal consisting of a secondtri-slit, the second seal including rounded and flat sides locatedaround a perimeter of the second seal, each side including at least oneinterlocking member directly attached to the second seal; and a thirdseal disposed co-axially and proximal to the first seal and the secondseal, the third seal including a central opening, wherein a space islocated between the second and third seal, the space created by thesecond and third seal, wherein the interlocking members of the firstseal and the interlocking members of the second seal interlock with eachother such that the rounded sides of the first seal are located adjacentto the flat sides of the second seal.
 15. The cannula of claim 14wherein the cap comprises a plurality of suture retaining features formanagement of sutures during a surgery.
 16. The cannula of claim 15wherein the suture retaining features comprise tabs.
 17. The cannula ofclaim 14 wherein the first tri-slit and the second tri-slit are offsetby an angle α.
 18. The cannula of claim 17 wherein the angle α is about180°.
 19. The cannula of claim 14 further comprising a channel definedby the first tri-slit, the second tri-slit, and the central opening,wherein fluid leakage during surgery is limited to the channel.
 20. Thecannula of claim 14 wherein the first seal and the second seal areconfigured to form a seal against sutures.
 21. The cannula of claim 14wherein the third seal is configured to form a seal against shaftedinstruments.
 22. The cannula of claim 14 wherein the central openingcomprises a diameter of between 0.060 inches and 0.120 inches.
 23. Thecannula of claim 14 wherein the third seal comprises a syntheticmaterial.
 24. The cannula of claim 14 wherein the third seal comprises apolymer material.
 25. The cannula of claim 24 wherein the polymermaterial comprises polyisoprene.
 26. A seal assembly comprising: a firstseal including a first tri-slit, the first seal including rounded andflat sides located around a perimeter of the first seal, each sideincluding at least one interlocking member directly attached to thefirst seal; a second seal disposed co-axially and proximal to the firstseal and including a second tri-slit, the second seal including roundedand flat sides located around a perimeter of the second seal, each sideincluding at least one interlocking member directly attached to thesecond seal; and a third seal disposed co-axially and proximal to thefirst seal and the second seal, the third seal including a centralopening, wherein the interlocking members of the first seal and theinterlocking members of the second seal interlock with each other suchthat the rounded sides of the first seal are located adjacent to theflat sides of the second seal.
 27. The seal assembly of claim 26 whereinthe interlocking members of the sides of the first and second sealsinclude tabs or detents.
 28. The seal assembly of claim 27 wherein thetabs and detents interlock with each other.
 29. The seal assembly ofclaim 26 wherein the interlocking of the interlocking members of thefirst seal and the interlocking members of the second seal facilitatespositioning of the first tri-slit and the second tri-slit at an angle αrelative to each other.
 30. The seal assembly of claim 29 wherein theangle α is about 180°.
 31. A cannula comprising: a housing including aproximal portion and a distal portion, the proximal portion including aplurality of columns, each column individually and directly attached toan inner perimeter of the proximal portion; and a seal assemblycomprising a first seal, the first seal including rounded and flat sideslocated around a perimeter of the first seal, each side including atleast one interlocking member directly attached to the first seal; asecond seal disposed proximal to the first seal, the second sealincluding rounded and flat sides located around a perimeter of thesecond seal, each side including at least one interlocking memberdirectly attached to the second seal; and a third seal disposed proximalto the second seal, wherein each seal includes a plurality of openings,the seal assembly located in the proximal portion of the housing suchthat the columns are housed within the openings, the interlockingmembers of the first seal and the interlocking members of the secondseal interlock with each other such that the rounded sides of the firstseal are located adjacent to the flat sides of the second seal.
 32. Aseal assembly for a cannula, the seal assembly located in a proximalportion of the cannula, the proximal portion being a single component,the proximal portion, including a plurality of columns, each columnindividually and directly attached to an inner perimeter of the proximalportion, the seal assembly consisting of: a first seal including a firsttri-slit, the first seal including rounded and flat sides located arounda perimeter of the first seal, each side including at least oneinterlocking member directly attached to the first seal; a second sealdisposed proximal to the first seal, the second seal including a secondtri-slit, the second seal including rounded and flat sides locatedaround a perimeter of the second seal, each side including at least oneinterlocking member directly attached to the second seal; and a thirdseal disposed proximal to the second seal and including a centralopening, wherein a space is located between the second seal and thethird seal, the space created by the second and third seal, wherein eachseal includes a plurality of openings, the seal assembly is located inthe proximal portion of the housing such that the columns are housedwithin the openings, the interlocking members of the first seal and theinterlocking members of the second seal interlock with each other suchthat the rounded sides of the first seal are located adjacent to theflat sides of the second seal.
 33. A cannula comprising: a singlecomponent housing having a proximal portion and a distal portion, theproximal portion including a plurality of columns, each columnindividually and directly attached to an inner perimeter of the proximalportion; and a seal assembly located in the proximal portion of thehousing, the seal assembly consisting of: a first seal including a firsttri-slit, the first seal including rounded and flat sides located arounda perimeter of the first seal, each side including at least oneinterlocking member directly attached to the first seal; a second sealdisposed proximal to the first seal, the second seal including a secondtri-slit, the second seal including rounded and flat sides locatedaround a perimeter of the second seal, each side including at least oneinterlocking member directly attached to the second seal; and a thirdseal disposed proximal to the second seal and including a centralopening, wherein a space is located between the second seal and thethird seal, the space created by the second seal and the third seal,wherein each seal includes a plurality of openings, the seal assemblylocated is in the proximal portion of the housing such that the columnsare housed within the openings, the interlocking members of the firstseal and the interlocking members of the second seal interlock with eachother such that the rounded sides of the first seal are located adjacentto the flat sides of the second seal.
 34. A seal assembly for a cannula,the cannula comprising a single component housing having a proximalportion and a distal portion, the proximal portion including a pluralityof columns, each column individually and directly attached to an innerperimeter of the proximal portion, the seal assembly comprising: a firstseal including a first tri-slit, the first seal including rounded andflat sides located around a perimeter of the first seal, each sideincluding at least one interlocking member directly attached to thefirst seal; a second seal disposed co-axially and proximal to the firstseal, the second seal including a second tri-slit, the second sealincluding rounded and flat sides located around a perimeter of thesecond seal, each side including at least one interlocking memberdirectly attached to the second seal; and a third seal disposedco-axially and proximal to the first seal and the second seal, the thirdseal including a central opening, wherein the seal assembly is locatedin the proximal portion of the housing, wherein a space is locatedbetween the second and third seal, the space created by the second andthird seal. wherein each seal includes plurality of openings, the sealassembly is located in the proximal portion of the housing such that thecolumns are housed within the openings, the interlocking members of thefirst seal and the interlocking members of the second seal interlockwith each other such that the rounded sides of the first seal arelocated adjacent to the flat sides of the second seal.
 35. The sealassembly of claim 26 wherein the first seal and the second seal bothinclude two rounded sides and two flat sides.